A square with side length $c$ has an area of $81$ square centimeters. The following equation shows the area of the square. $c^2 = 81$ What is the side length of the square in centimeters?
Solution: Let's solve for $c$. Remember that it is not possible to have a negative side length! $ $ $\begin{aligned} c^2 &= 81\\ \\ \sqrt{c^2} &= \sqrt{81}\\ \\ c&= 9 \end{aligned}$ The side length of the square is $9 \text{ cm}$.